The overall objectives of this research proposal are to understand the mechanism of, Scope, and significance of the reactions concerned with methylation of the contractile proteins of skeletal muscle and of Physarum polycephalum and to examine these processes as a part of the development and differentiation of these systems. The goals of this investigation include 1) studies of the properties and distribution of the protein methylases, using embryonic and cultured chick skeletal muscle and Physarum polycephalum plasmodia; 2) studies on the methylases and patterns of methylation and synthesis of myosin and actin in differentiating skeletal muscles and in P. Polycephalum; 3) investigation of the functional significance of protein methylation in P. polycephalum by study of an appropriate selection of mutants that have been screened for defects in motility, the contractile proteins, and methylation reactions.